Richard Hayler (Deloitte), fellow of the ICAEW, offers a ‘formula for finite life project cashflows’ that modifies earlier models to achieve ‘a more realistic assumption set.’ 'Post- to Pre-Tax Discount Rates: Not a Simple Conversion,' published last month in Journal of Business Valuation and Economic Loss Analysis, recognises that value assessments are generally made post-tax, but comments that ‘from time to time, analysts could sometimes benefit from a "shorthand" to ascertain and apply a pre-tax discount rate to discount pre-tax cashflows.’ These situations might include regulatory returns or impairment testing of business units.